Relationship between age and learning languages

Critical Period Hypothesis

The CPH, which is often linked with Chomsky’s work, has been under discussion for decades. The theory is that we are genetically programmed to learn a language in our early years of life. When this period comes to an end, the process of learning a language becomes much more arduous.

As you might expect, there is limited evidence either for or against this hypothesis. Almost all young children are exposed to plentiful samples of their native languages. Perhaps as a result of this lack of evidence, the debate continues over whether our ability to learn a language declines sharply at a particular age.

Supporters of the hypothesis have failed to come to a consensus on when the ‘critical period’ ends. Some theorists are of the opinion that the ‘critical period’ ends at the age of 5 or 6, whereas others believe that it lasts until children are 12 or even 15. Researchers who believe that our ability to learn a language deteriorates more gradually often talk about a ‘sensitive’ rather than a ‘critical’ period.

The Critical Period Hypothesis originally focussed on children acquiring their first language. However, it has often been extended to include second language acquisition and this has proved to be even more controversial. Although older learners of a second language often struggle to compete with the native-like fluency that younger learners can achieve, adults who start studying a second language do have the capacity to master the language and communicate very successfully.

Research suggests that some areas of linguistics, such as pronunciation, are more affected by the age of the learners. Almost all adult learners, even those who can make extremely effective use of a full range of grammatical structures and vocabulary, retain a foreign accent. This, combined with occasional grammatical slips or slightly unnatural use of word choice or collocation, sets them apart from monolingual native speakers of the language, or second language learners who started learning when they were children.

Interestingly, a recent study conducted in 2018 by Massachusetts Institute of Technology in the US supports the Critical Period Hypothesis for second language learners. It found that learners who wish to achieve a native-speaker proficiency in a new language need to start learning before the age of 10.